Technical Field
The present disclosure relates to a front passenger seat airbag device.
Related Art
Front passenger seat airbags are conventionally known that include a first airbag section inflated and deployed at the vehicle front side of an occupant seated in a front passenger seat, and a second airbag section positioned at the vehicle width direction inner side of the first airbag section and bulging out further toward the vehicle rear side than a rear end of the first airbag section (see, for example, Japanese Patent Application Laid-Open (JP-A) Nos. 2016-037127 and 2015-231808). Since a front passenger seat airbag with the above structure has left-right asymmetry in a vehicle plan view, it may be referred to as a “front passenger seat airbag having a left-right asymmetrical structure” in the explanation below. Furthermore, in the explanation below, an occupant seated in the front passenger seat is referred to as a “front passenger seat occupant” and an occupant seated in the driving seat is referred to as a “driving seat occupant”.
In a front passenger seat airbag device described in JP-A No. 2016-037127, a spacer or the like with a height equivalent to a difference in respective folded heights is set on the first airbag section side of a back face of an airbag door, due to the folded height of the first airbag section being lower than the folded height of the second airbag section. Thus, deployment load from the first airbag section and deployment load from the second airbag section received by the back face of the airbag door are made substantially uniform and the airbag door is opened out without any bias toward the left or right, enabling the deployment behavior of the front passenger seat airbag having a left-right asymmetrical structure to be stabilized.
However, in the case of the front passenger seat airbag device described in the above documents, configuration is such that the spacer or the like is set on the first airbag section side of the back face of the airbag door, such that the first airbag section forcefully strikes the spacer when the front passenger seat airbag is inflated and deployed. It is therefore conceivable that the spacer or the like might fall off the back face of the airbag door.
In a front passenger seat airbag device described in JP-A No. 2015-231808 also, a folded height (“folded height H2”) of the second airbag section is slightly higher than a folded height (“folded height H1”) of the first airbag section. When a first inflator and a second inflator with different heights to each other in a first modified example illustrated in FIG. 5B are applied to the front passenger seat airbag illustrated in FIG. 1 of JP-A No. 2015-231808, an upper face of the higher-height first inflator elevates the first airbag section that has a relatively low folded height. This enables a similar effect to that of the spacer of the front passenger seat airbag device described in JP-A No. 2016-037127 to be expected.
However, a different issue arises in the case of the front passenger seat airbag device described in JP-A No. 2015-231808. Namely, in this front passenger seat airbag device, a folded width (“folded length L2”) of the second airbag section in a folded state is set longer than a folded width (“folded length L1”) of the first airbag section in a vehicle plan view. The purpose of this is to utilize initial inflation of a base portion positioned between the first airbag section and the second airbag section to inflate and deploy the second airbag section prior to the first airbag section. Thus, supposing that the first inflator and the second inflator with different heights to each other illustrated in FIG. 5B were applied to the front passenger seat airbag illustrated in FIG. 1A of JP-A No. 2015-231808, despite being able to eliminate the possibility that a spacer may fall off or the like, this would not change the fact that the second airbag section with the longer folded length opens out the airbag door prior to the first airbag section with the shorter folded length. Thus, in the case of this front passenger seat airbag device, a substantially uniform deployment load cannot be made to act on the back face of the airbag door and the airbag door cannot be made to open out substantially uniformly on both left and right sides.
Thus, in the technology of the documents described above, it is difficult to both prevent a spacer from falling off or the like during inflation and deployment of the first airbag section, and to open out an airbag door substantially uniformly so as to stabilize the deployment behavior of the front passenger seat airbag having a left-right asymmetrical structure, and there is room for improvement of the technology described in the above documents regarding these points.